The present invention relates to the fields of roofing and/or siding and, more particularly, is directed towards a pre-assembled panel of shingles or shakes as used in construction as a protective covering for roofs and/or sidewalls.
Although shakes and shingles are usually produced from Western Red Cedar or Eastern White Cedar, there are numerous durable rot resistant woods that can be used effectively. Additionally, various natural and synthetic materials can be used to produce shingles that would be appropriate for use with this invention. For simplicity, the terms “shingle” or “cedar shingle” will be used as representative of shingles or shakes of any composition.
While shingles are not defined by the material they are made from, they can be defined as having a unique form and function. Shingles function as a precipitation barrier through the use of large overlaps. In a typical roof installation, only ⅓rd of the shingle is exposed resulting in 3 layers of shingles at any given point in the installation. Any water that leaks through joints between adjacent shingles is redirected to the surface by shingles in the underlying course. This requires that the joints in the underlying course be offset sufficiently from the joints in the upper course to prevent further leaking. In comparison, joints between adjacent sections of lap siding must be sealed to prevent leaks because the overlap from course to course is typically only a fraction of the exposed area. Overlaps are not designed to redirect water to the surface, and a waterproof installation would require all exposed joints to be perfectly sealed. The large size of the siding sections make it difficult to maintain leak-proof seals when the siding expands and contracts with changes in temperature and humidity. The open joints of a shingle installation are designed to accommodate these changes without developing leaks.
Cedar shingles have been used for hundreds of years as a premium roofing and siding material, and have a proven history of durability and superior weatherproofing when properly installed.
While cedar shingles are one of the most waterproof solutions for roofing or siding, they also provide better ventilation than most other materials. The keyways (the vertical gaps between adjacent shingles), relatively course surface texture, and the natural distortions in the material, all provide numerous small airways between shingles. These airways provide ventilation which allows any moisture that has accumulated in the wall or roof to dry to the outside. Even if the shingled surface is entirely waterproof in the most extreme weather, water will be formed when warm moist air that has migrated into the wall or roof structure cools and condenses. Since a vapor barrier is typically installed on the interior side of the wall or roof, it is important that the siding be ventilated well enough to allow this moisture to dry to the outside. If moisture accumulates within the wall structure, and does not have a way to dry out, mold and other fungi that cause rot and decay will thrive.
Essentially, if a typical residential building is otherwise properly maintained and constructed, the lifespan of the structure will be determined by the performance of the roofing and siding. It is significant to note that research following the 2004/2005 hurricane season in Florida has determined that about 90% of the homes that were destroyed had no significant wind related structural damage, but were destroyed by rampant decay in saturated walls. The exterior walls were insufficiently waterproof to shed wind driven rain, and water wicked through housewraps at fastener locations and overlaps. Once saturated, the walls were insufficiently ventilated to allow the walls to dry out.
Understanding the importance of good ventilation, builders have explored the “rain screen” wall concept, which separates the siding from the sheathing to create an airspace which can be ventilated. While it is somewhat difficult to create the airspace, it is very difficult to ventilate it. Typically the ventilation is insufficient, and the airspace created by the rain screen wall becomes another site for condensation, much like the wallspace behind it. Conventional cedar shingles provide better ventilation than stucco, brick, clapboard, panelized, or cementitious siding. However, depending on a variety of conditions, even cedar shingles may not provide sufficient ventilation.
While cedar shingles provide a superior ability to shed precipitation and superior ventilation, they also are considered to be one of the most aesthetically pleasing solutions for roofing and siding. Shingles provide detail for flat surfaces, and the characteristics of the detail can be varied considerably by the size, exposure, type, and finish of the shingles. Cedar shingles are often presented by builders as a premium option over other types of siding and roofing.
Cedar shingles also contribute to the energy efficiency of the structure. Tests have shown that, in hot weather, sheathing under cedar shingles is up to 40° cooler than sheathing under asphalt/fiberglass shingles, which can reduce cooling costs significantly. During cold weather, cedar shingles, because of their low density, provide better insulation than other types of roofing and siding materials. More importantly, well ventilated dry insulation performs much better that wet insulation.
Although there are many advantages to cedar shingles, there are significant problems related to the installation of this product.
One of the most significant problems involves the size and position of the joints between adjacent shingles. Guidelines and building codes for the installation of cedar shingles require a space or keyway between adjacent shingles to allow for expansion of the shingles when they become wet. The keyways must be accurately and consistently sized for both function and appearance. Keyways that are too narrow will not allow shingles to expand enough when they become saturated, which will cause the shingles to buckle.
Additionally, according to generally accepted guidelines and building codes, keyways must be horizontally offset from keyways in the next 2 and previous 2 courses for roofing, and in the next and previous course for siding. The required minimum offset distance is 1½″. Shorter offset distances will result in leaks when wind driven precipitation is blown sideways between shingles to nearby keyway locations. Adhering to this requirement, however, makes the process of installing shingles very time consuming and tedious.
A good professional installation requires planning for keyway spacing, as well as planning for an aesthetically balanced distribution of random width shingles. It's important to avoid patterns that will stand out, such as a cluster of small or large shingles or a diagonal pattern of same-size shingles. A good installer spends a significant amount of time choosing the right shingle from a supply of random width shingles, as well as cutting shingles to the required width. The more diligent the installation, the more time consuming the installation process becomes. Often, installers simply fail to adhere to the codes because the process is too time consuming. Shingle manufacturers indicate that nearly all warranty claims are the direct result of improper installation.
Another problem associated with cedar shingles is that the natural tannins in the wood can, according to some studies, degrade the water repellency of some vapor permeable housewraps. The smooth surface of newer housewraps also has a tendency to “wick” water through fastener holes and overlaps, when any type of siding lays flat against the housewrap. This capillary action can result in very significant amounts of water being drawn into the wall. Another problem related to this is the tendency for shingles to warp or “cup” when moisture remains trapped between the shingles and the housewrap after the front of the shingles dries out.
There have been several attempts to develop products that address some of the problems outlined above. Products such as CEDAR BREATHER, a nylon 6 matrix, and textured or dimpled housewraps have been developed to create an airspace between the shingles and the housewrap or sheathing. These may provide some benefit because they provide a capillary break between the shingles and the housewrap where water could otherwise become trapped and wick through the housewrap. However, as discussed previously with respect to rainscreen walls, ventilating this newly created airspace is very difficult. It requires continuous vents at the upper and lower edges of the roof or wall, as well as above and below all windows, chimneys, dormers, etc. Even with all vents in place it is still not possible to provide adequate ventilation to prevent condensation cycles from occurring to some degree in this air space.
It is interesting to note that the company that marketed the nylon 6 matrix as CEDAR BREATHER has introduced a newer product that includes drainage channels. The benefit of the capillary break is offset by condensation that forms in the airspace used to create the capillary break. For walls with vapor permeable housewraps, as temperature and pressure build up in this airspace, the moisture from condensation vaporizes and passes through the housewrap into the wall structure.
Products have also been developed to make the installation of cedar shingles less tedious and time consuming. A number of shingle panels have been patented and/or marketed as a means to install a group of shingles at one time. These concepts generally fall into three categories.
The first category includes panels comprised of shingle segments attached to a sheet of plywood or similar material, with the sheet fully or nearly fully containing the shingle segments. This type of panel provides a cedar shingle “look”, but the panelized shingle segments do not function as shingles. These products are essentially panelized or lap siding embellished with cedar shingle segments. As such, they can claim the durability and beauty of cedar, but they do not have the superior weatherproofing capacity of shingles.
Additionally, when shingles are installed conventionally, a waterproof layer of housewrap and flashing protects the sheathing from any exterior moisture that gets past the shingles. With shingle panels, the shingle segments are already attached to a layer of sheathing, and both elements are installed as one unit, leaving no opportunity to provide a waterproof layer between them. Although some panels are manufactured with a housewrap between the shingles and the base layer, there is still no opportunity to protect the edges of the base layer, especially when the panel is cut at door and window openings. Another disadvantage of this type of panel is that, because the panel is not a structural element (because there are limitations in how it can be fastened), it must be installed over standard sheathing. This is not only wasteful but causes the siding surface to project further outward than normal creating problems with the fit of window and door trim. In addition, the code required vapor permeable housewrap that has already been applied to the sheathing is now sandwiched between two layers of sheathing, greatly diminishing its ability to vent water vapor, and increasing the potential for trapped moisture and condensation inside the wall. In addition, panels of this type must be cut with a saw, rather than a knife, as with conventional shingles. Since this must be done on the ground, rather than on the scaffolding, it offsets some of the time savings gained by installing larger units.
Still another disadvantage of this type of panel is that it depends on a special overlapping joint to connect the panels left to right in a course. Because panels cannot be joined without this special joint, panel sections that are cut off at the end of each course, and at doors, windows, etc. cannot be rejoined with other sections. Depending on the size of the wall and the frequency of surface interruptions, this can result in a very high percentage of waste. The alignment of keyways with this type of panel is irrelevant because these panels do not function as shingles. The top and bottom edges of the panels overlap slightly to enable drainage from one panel course to the next, but all joints must be sealed to prevent leaks. Clearly, the horizontal and vertical joints between panels have a much greater potential to leak than conventionally installed shingles. For this reason, these panels can only be used for sidewalls, and not for roofs.
The second category of existing shingle panels includes shingles that may be up to full size, and are joined together by rigid backerboard that attaches only to the upper portion of the shingles, allowing the lower portion of the shingles to overlap the previous course. These panels function to some degree as shingles, but cannot provide triple layer coverage. These panels are also not sufficiently waterproof to allow them to be used as roofing. Because the backerboard functions as a second layer of sheathing, these products share many of the same problems outlined above for panels with full backerboards.
The third type of panel uses a board that joins shingles together by attaching to the front side of the shingles. In one instance, the board is attached to the exposed part of the shingles and is removed after the upper portion is attached to the wall. This leaves fastener holes in the exposed part of the shingles. There is also the possibility that the shingles will split when the board is being removed. In addition, if the panels are left in sunlight prior to installation, the part of the shingle that is not covered by the board will darken significantly, resulting in an uneven appearance when installation is complete.
Other panels of this type use a thin narrow board that joins the shingles at the top of the front side with a board that is thin enough that it can stay in place during installation. However, the board is thick enough that it eliminates the bowed shape that shingles normally assume when they span between the previous course and the sheathing. This bowed shape provides a spring like tension that helps shingles stay flush against the previous course. With this type of panel, shingles don't lay flat and flush on the previous course. Because of the connecting board, a space is created between the layers of shingles. This space allows wind blown precipitation to move sideways between layers where it can access underlying keyways and pass through to the sheathing. Again, as with the other panels, this type of panel is less waterproof than conventionally installed shingles and cannot be used for roofs.
In addition, because this panel is joined only with a thin board attached to the thin end of the shingles, the panel is relatively fragile. Shingles can be easily damaged or knocked out of alignment. Because of its lack of strength, the panel is necessarily limited to a relatively short width, which is too short to provide sufficient keyway offsets over multiple courses and eliminate diagonal patterning. Following the instructions for the installation of this product actually results in keyway placement that does not meet building code requirements.
In fact, none of the panels that I am aware of, and that function to some extent as shingles, adequately addresses the issue of keyway spacing. Typically, single course panels are installed with each successive course offset a fractional width of the first shingle in the panel. This results in a strong diagonal pattern of every element in the panel. Another problem common to all of these panels is that the addition of a backer board makes it more difficult to pack and ship the panels, adding significant weight and volume, increasing shipping costs as well as increasing the effort required to move and install the product at the job site.
Thus, there is a need in the art for a pre-assembled set of shingles (the “shingle set”), together with an installation system. More particularly, there is a need in the art for a shingle set that meets one or more of the following criteria:
will enable a much more rapid installation of shingles as compared to the conventional method of installing shingles one at a time;
will not compromise the function and performance of the individual shingles in the set as compared to individual shingles properly installed in a conventional manner;
will include markings or guidelines to indicate the proper placement of each subsequent shingle set during installation, as necessary to maintain a pattern of proper keyway offsets;
will be such that persons with little or no particular knowledge, relevant experience, or skill, can feasibly install the product and achieve results of the highest possible quality;
will result in keyway offsets of at least 1½″ over the next 2 and previous 2 courses without requiring the normal planning or decisions of the typical shingle installer;
will result in a balanced distribution of various shingle widths and no apparent repetitive patterns, without requiring the normal level of planning or decisions of the typical shingle installer;
will be interconnected in a manner that does not add significant thickness to the shingles and will not affect the position of the shingles or how the shingles lay with respect to each other and the underlying sheathing, as compared to conventional installation, thus maintaining function and performance in line with conventionally installed shingles;
will be interconnected in a manner that allows the set to be cut with a knife rather than a saw;
will be interconnected in a manner that does not add significant thickness, allowing the shingles to be stacked flat and shipped without the use of spacers and without significant additional weight and volume;
will be such that keyways are of a precise and consistent width;
will be manufactured such that the method of securing shingles in position in the set will provide measures to prevent shingles to be knocked out of alignment or easily damaged during shipping and handling (i.e., the shingle set will be durable enough that it can be handled in a manner typical of construction finishing products without damage);
will be such that the method of securing the shingles allows the shingles to expand and contract in a conventional manner;
will be such that the natural ventilating ability of shingles is further enhanced by including a number of ridges applied to the back of the shingles and running vertically.
Thus, there is a need in the art for an improved shingle apparatus and system.